Sing! Karaoke by Smule Description

With cool vocal effects, the option to record voice and video and even collaborative music-making, this is one hell of a karaoke app. It’s just a shame that the best pop songs are paid-for only, so you are left with slim pickings if you’re not willing to part with your cash.

Editors Notes:There’s a fairly decent selection of songs, mostly American pop. Being able to add your vocals to a friend’s is especially cool. The gameplay itself is very smooth indeed: the app accurately assesses your pitch and timing, and produces a nice recording.